/*
 * Copyright 2004-2011 Paolo Conte
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.jellylab.ojoverse;

import java.util.List;

public class Paginator {

    /**
     * Create a Pager for the current page
     * @param elems Elements to paginate
     * @param page Page number
     * @param entries Number of entries for page
     * @return
     */
    public Pager paginate(List elems, int page, int entries) {
        int pages = elems.size() / entries;
        int from = entries * (page - 1);
        int size = elems.size();
        if(size > entries) {
           size = entries;
        }
        int to = from + size;
        List sublist = elems.subList(from, to);
        Pager pager = new Pager(sublist, pages);
        return pager;
    }
    
    /**
     * A simple container for paging informations
     */
    public static class Pager {
        // the elements to show
        public List sublist = null;
        // total pages number
        public int pages = 0;

        public Pager(List sublist, int pages) {
            this.sublist = sublist;
            this.pages = pages;
        }
    }

}
